The White House has warned gun manufacturers that it will not allow them to circumvent a new proposed ban on military-style semi-automatic rifles in the way they successfully undermined the previous 1994 federal prohibition.

Calling for the reinstatement of the federal ban, that was allowed to lapse in 2004, Barack Obama made clear that he would not tolerate the same tactics that permitted the makers of assault rifles to wriggle around the restrictions. A White House paper setting out the proposed changes made the challenge to gun makers explicit.

The 1994-2004 ban, it said, "was an important step, but manufacturers were able to circumvent the prohibition with cosmetic modifications to their weapons. Congress must reinstate and strengthen the prohibition on assault weapons."

The emphasis on "strengthening" the revised federal ban will send alarm bells ringing in the headquarters of the biggest US gun manufacturers. During the 10 years that Bill Clinton's ban was in place, the law was diluted by gun makers who made small cosmetic changes to the design of their weapons as a way of freeing them from federal controls.

The change might be as insignificant as moving a single screw in the firearm, but that was deemed sufficient to change the name of the weapon, remove it from the prohibition, and put it back on sale. Banned weapons were blatantly copied, with a minor design change, and again renamed and remarketed.

For instance, the Bushmaster XM15 that was deployed in Sandy Hook elementary school last month to kill 20 young children, six of their carers and the gunman's mother, was a copy conceived under the shadow of the Clinton assault rifle ban of the prohibited Colt AR-15.

Josh Horwitz, director of the Coalition to Stop Gun Violence, said it was crucial that the White House was aware of how the Clinton ban was undermined last time round and was determined not to let the same thing happen again. "This is very important. Unfortunately, the gun industry doesn't act in the spirit of the law – you have to hem them in effectively with watertight legal drafting."

An awareness of the tricks that gun manufacturers can play to sidestep the law has informed Senator Dianne Feinstein's bill on revising the federal ban on assault rifles that may form the template of the White House plans. She has modelled the bill on her home state of California, which still has on its book a prohibition on military-style AR-15s that has proved to be much more effective than Clinton's federal ban.

One of the key features of California's approach was that it requires only one designated feature of the gun to bring it under the remit of a ban, whereas the 1994 federal law allowed two features, thus making it all the easier for gun makers to run roughshod over the legislation. Sam Hoover, a staff lawyer with the Law Center to Prevent Gun Violence, said the Obama administration should build into its ban a provision that gave the justice department the discretion to introduce additional forbidden features in order to thwart the tactics of gun makers.

"Whatever the White House does, gun manufacturers will still sit around and try to figure out ways to get their weapons back on the market by adjusting designs to fall outside the test. But it's encouraging that Obama is fully aware of this and determined to pre-empt it."